US2938494A - Apparatus for solder coating - Google Patents

Description

May 31 1960 R. w. wAMPLER ETAL 2,938,494

APPARATUS FOR SOLDER coATING May 31, 1960 R. w. WAMPLER ET Ax. 2,938,494

APPARATUS FOR SOLDER COATING Filed Nov. 1, 1S52 l5 Sheets-Sheet 2 115 zog L52 97 5211-1 Gttorneg May 31, 1960 R. w. WAMPLER Em 2,938,494

APPARATUS FOR SOLDER COATING 15 Sheets-Sheet. 3

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APPARATUS FOR SOLDER COATING 15 Sheets-Sheet 8 Filed Nov. 1. 1952 151 f1 A i.. 3 /111 Cttornega May 31, 1950 R. w. wAMPLER z-:TAL 2,938,494

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APPARATUS FOR SOLDER COATING Filed NOV. l, 1952 15 Sheets-Sheet 12 mventorzi May 31, 1960 R.'w. wAMPLl-:R ET AL 2,938,494

APPARATUS FOR SOLDER COATING Filed Nov. l, 1952 15 Sheets-Sheet 13 May 31, 1969 R. w. WAMPLER r-:TAL 2,938,494

APPARATUS RoR SOLDER coATING Filed Nov. l, 1952 15 Sheets-Sheet 14 m4 5,11 5,71 571'571 afm 5,14 anp fn/'It I l| 1J.. n 567 O O O 56o O 27 566 A n O ,661 O May 31, 1960 R. w. wAMPLr-:R ETAL 2,938,494

APPARATUS FOR SOLDER COATING Filed Nov. l, 1952 l5 Sheets-Sheet 15 l l 7g 408 L I 425 426 79 78 77 409% O G+ 09 Gttornegs United States Patent O APPARATUS FOR SOLDER COATING Roy W. Wampler and Charles M. Browne, Toledo, Ohio,

assignors to Libbey-Owens-Ford Glass Company, Toledo, Ohio, a corporation of Ohio Filed Nov. 1, 1952, Ser. No. 318,170

Claims. (Cl. 118-74) The present invention relates to the tinning or solder coating of metal surfaces, and more particularly to an improved method and apparatus for continuously tinning metallized surfaces on glass sheets that are.to be used in the production of multiple glass sheet glazing units.

Briefly stated, by the method of the invention, a metal, or metallized surface can be subjected to a reducing atmosphere, burnished, fluxed and finally coated uniformly with solder or other bond-inducing metal in a succession of continuing operations while the surface is moving forward along a definite predetermined path.

` This application is a continuation-impart of'our copending application, Serial No. 792,698, iiled December 19, 1947, now abandoned.V

The primary object ofthe invention is to provide a completely automatic means .of rapidly and effectively tinning or solder coating a metal surface in an eflicient and economical manner that will lend itself to the continuous commercial production of articles having soldered or sweated joints.

Among the more specific objects is the provision of a special type of conveying and positioning or aligning mechanism whereby the work to be treated will be properly presented to the successive conditioning and treating elements during its travel along the tinning line.

Another object is to provide a novel burner means for subjecting a metal surface, andA particularly a newly formed metal surface, to a reducing flame for the purpose of reducing the oxides which are formed by oxidation of the metal when exposed to the air. r

Another object is the provision of novel means for burnishing the metal surface to remove projections and loose particles and to smooth and level the surface to be tinned.

Another object is to provide a special apparatus for applying iiux to the reduced and burnished metal surface to be tinned.

Another object is the provision of novel means for depositing a predetermined amount of solder in drop formation to the uxed surface.

Another object is to provide a heated tool of novel construction for spreading or ironing the above mentioned drops of solder into a smooth, even and uniform coating that is tightly adherent to the metal surface.

Still another object is the provision of a plurality of sets of reducing, burnishing, uxing and solder applying elements disposed along a continuous tinning line, together with means in advance of and interposed between the several sets for positioning, aligning, and turning the work whereby four metallized marginal portions of a glass sheet can be treated successively while such sheet is continuously moving in a substantially straight line.

Other objects and advantages of the invention will become more apparent during the course of the following description, when taken in connection with the accompanying drawings.

In the drawings, wherein like numerals are employed to designate like parts throughout the same:

ice

Fig. 1 is a perspective view of a completed all glassmetal multiple sheet glazing unit;

Fig. 2 is an enlarged sectional view of one edge of the unit of Fig. 1, showing the metal separator strip soldered to metallized coatings on the glass sheets;

Fig. 3 is a perspective view of a corner of a glass sheet illustrating the sequence of operations in the soldering or tinning technique of the invention;

Fig. 4 is a plan view of a tinning line constructed in accordance with the invention;

Fig. 5 is a side elevational view of the line of Fig. 4;

Fig. 6 is an enlarged view of one portion of the line illustrated in Fig. 5, showingthe mechanism by which a glass sheet after being tinned along one margin is rcpositioned, tinned or solder coated along the opposite margin, and then again repositioned for subsequent solder coating of another margin; f

Fig. 7 is a top view also on an enlarged scale vof the portion of the line shown in Fig. 6;

Fig. 8 is a transverse sectional view taken substantially on the line 8-8 indicated in Fig. 6, showing the registration of the glass against a ilexible'aligning unit;

Fig. 9 is a fragmentary sectional View through the conveyor shown in Fig. 8 and upon which glass sheets are carried through the line and may be shifted transversely to the direction of their general movement;

Fig. 10 is a partial top view on an enlarged scale of the aligning unit shown in Fig. 8;

Fig. 11 is a fragmentary, perspective, detail view of the flexible aligning elements of the aligning unit;

Fig. 12 is a fragmentary cross section of the supporting and retaining members for the aligning elements shown in Fig. 1l;

Fig. 13 is a section taken on the plane of the line 13-13, in Fig. 10, and illustrates the drive mechanism for the aligning unit;

Fig. 14 is a section taken on the plane of the line 14-14 as indicated in Fig. 7, and is generally an end view of one of the sets of reducing, burnishing, fluxing,

and solder applying elements disposed along the line.'v

The supporting, conveying, and hold down mechanisms for the glass sheets are also shown;

Fig. 15 is a fragmentary detail view, partly in secgon, lotf the conveying and supporting means shown in Fig. 16 is a partial top view of one of the sets of elements mentioned in the description of Fig. 14;

Fig. 17 is a view of a section taken substantially on the line-1717 indicated in Fig. 6, showing a side view of the unit which applies a reducing ame to the oxidized metal coating;

Fig. 18 is a front elevational view of shown in Fig. 17;

Fig. 19 is a front elevational viewof the burnishing or abrading unit;

Fig. 2O is a view in perspective of the supporting framework for the burnishing unit; l

Fig. 2l is a view of a section taken on the line 21-21 in Fig. 19, through the burnishing unit;

Fig. 22 is a View of a part of the rear of the unit shown in Figs. 19 to 21, to illustrate particularly the methodV whereby the burnishing brushes are reversed in the di rection of theirrotation;

Fig. 23 is an end view of the burnishing unit illustrating the lift control for the brushes;

Fig. 24 is a sectional view through the glass holddown device;

Fig. 25 is a fragmentary side view of a portion of the hold-down device;

Fig. 26 is a front elevational view of the ilux dispensing unit, showing the tiux applying wheel in AContact with the glass sheet;

the reducing unit Pig. 27 is a side elevational view of the linx dispensing unit, showing the linx applying wheel in` the idle position, or in the position assumed between glass contact periods;

Fig. 28 is a View in perspective to illustrate the flux applying wheel and its contact to the glass, the parts of the unit being located as shown in Fig. 26;

Fig. 29 is a View of an electrical diagram showing how the ow of liquid ux, from the reservoir to the applying wheel of the flux dispensing unit, is automatically controlled;

Fig. 30 is a front elevational View of one of the solder depositing device;

Fig. 3l is a side elevational view of the solder depositing device shown in Fig. 30;

Fig. 32 is a top view of the same `solder depositing device;

Fig. 3.3 is an enlarged cross sectional view of the solder drop producing valve;

Fig. 34- is a partial top view of the solder coating unit and illustrates the relative locations of the solder depositing device and the ironing or spreading device; Fig. 34 taken in conjunction with Fig. 16 illustrates one complete set of reducing, burnishing, uxing, and solder appli/ing units;

Fig. 35 is a front elevational view of one of the solder ironing or spreading devices;

Fig. 3.6 is a view of a section taken on the line 36-36 indicated inA Fig. 35 and illustrates the means for adjusting the weight of the iron or spreading tool;

Fig. 37 is a view of a section taken on the line 37-37 as indicated in Fig. 35;

Fig. 3,8 is a fragmentary rear view of the same ironing device and particularly the control lever for the adjusting means;

Fig. 39 is a view of a section taken on the line 39-39 in Fig. 38. The view illustrates, in full and phantom lines, the lock and release of the control lever;

Fig. 40 is a vertical sectional view of the soldering or spreading iron or shoe and of the heating means and control therefor;

, Fig, 41 is a perspective View of the solder spreading iron in an inverted position to illustrate the solder Working surface;

Fig. 42 vis a bottom view of a modified form of soldering iron to be used on the second one of each pair of solder spreading devices;

Fig. 43 is a fragmentary side elevation of a part of the machine, showing an end of one of the solder applying units and the drive for one of the intermediate conveyors which are positioned between the tinning conveyors and the aligning conveyors;

Fig. 44 is a top view, in part, of one of the intermediate conveyors;

Fig. 45 is a section taken substantially on the line 45- 45 as indicated in Fig. 44;

Fig. 46 is a view similar to Fig. 42 of the working surface of a modiiied form of soldering iron;

Fig. 47 is a diagrammatic view illustrating the operation of the soldering irons;

Fig. 48 is a side elevation of a modiiied form of burnishng or abrading unit;

Fig. 49 is an end view of the unit of Fig. 48; and

Fig. 50 is a top or plan View thereof.

Although the solder coating method and apparatus of this invention is not limited to use in the production of any specific product, it has already proved vso valuable in the production of metal-to-glass seals in all glass-metal, multiple sheet glazing units, such as Libbey-Owens-Fords Thermopane, that it will be described in that connection here. i

Referring now more particularly to the drawings, there has been shown in Fig. 1 a multiple glass sheet glazing unit ofthepcharacter referred to above. As shown, the unit, which is designated in its entirety by the numeral comprises two sheets of glass 11 and '12 which are held in spaced face to face relation to one another by a separator strip 13 arranged between the two sheets, around the marginal portions thereof.

As best shown in Fig. 2, the separator strip 13 forms a part of a metal seal designated in its entirely by the numeral 14 and which is adapted to hermetically seal the air space 15 formed between the opposing faces of the glass sheets. The complete metal seal 14 includes tightly adherent, sprayed metal coatings 16 on the glass sheets, to which the separator strip 13 is secured by solder joints 17. I

In producing these units, the glass sheets are rst metallized by spraying the continuous metal bands or ribbons 16 around the marginal portions thereof. The second step is to tin or coat the metal bands with solder, and the nal oi' assembly step consists in sweating the metal separator strip 13, which has previously had its edge portions 18 and 19 coated with solder, to the tinned surfaces of the metal bands on the glass sheets.

The steps of metallizing the glass sheets, and the final assembly steps are fully described in the patent to C. D. Haven et al., 2,235,681, dated March 18, 1941, and form no part of the present invention.

However, it has been found in actual commercial production that this invention provides an improved method and apparatus for conditioning and tinning the meta-l coatings on the glass sheets preparatory tothe assembling Y operation, and that by employing the techniques of the invention, better, more permanent and more durable seals are obtained.

This is readily understandable because in ordinary use, such all glass and metal glazing units are subjected to differentialsv of temperature as in buildings where lthe outer sheet is exposed to seasonal climatic changes, while the inner sheet is exposed tothe more uniform and generally higher temperatures within the building. Similarly, in refrigerator cases, the inner sheet may be subjected to uniformly cold temperatures while the outer sheet is exposed to varying and considerable higher temperatures. These temperature differentials between the different .parts of the glazing unit cause one sheet of glass to expand or contract to a greater or lesser extent than the other sheet and set up a severe strain upon'the bond, or joint between the glass sheets and the separator means. Consequently, the success or failure of the unit can be said to hinge on `the solder joint between the metal separator and the metallized glass, and the tinning method and apparatus of this invention will insure an intimate bond between the solder layer and the metal coating on the glass. v

Briey stated, the apparatus of the invention comprises a continuous tinning line designated in its cntrety by the letter A (Figs. 4 and 5) and which is made up of a plurality of successive aligning conveyors B, F, J and N; intermediate conveyors C, E, G, I, K, M and O; and tinning conveyors D, H, L, and I. Disposed successively along the tinning line, some on one side of the line and some on the other, are a plurality of aligning units Q, R, S, and T; and sets of reducing, burnishing, fluxing and solder applying units indicated generally as U, V, W, and X.

In use, a glass sheet 20 to be tinned, and which has previously been metallized to provide tightly adherent marginal bands 16 thereon, is placed on the rst aligning' conveyor B and, during its movement thereover, is shifted transversely against the aligning unit Q to properly position the sheet for tinning of its lower short metallized edge a.

From the aligning conveyor B the glass sheet will pass over intermediate conveyor C onto the rst tinning conveyor D upon which it will be carried beneath each of the reducing, burnishing, uxing and solder applying units of the rst set, indicated at U, whereby a coating of solder will be applied to the metallized strip a. From this point, the sheet passes over the second intermediate conveyor E to the second aligning conveyor F where it is moved against the aligning unit R and then passes over thel third intermediate conveyor G to the second tinning conveyor H and under the set of reducing, burnishing, uxing and solder applying units V where the top short margin b will be tinned.

. Leaving the conveyor H, the sheet passes over intermediate conveyor I to aligning conveyor I. On this conveyor, the sheet is picked up by a vacuum frame Y and turned 90 to the position shown at Z, whereupon it is moved against the aligning unit S and positioned to pass over the intermediate conveyor K onto the third tinning conveyor L wherethe upper long margin c of the sheet will be tinned as it passes beneath the set of units W. Then, after passing over the next intermediate conveyor M onto the aligning conveyor N the sheet will be aligned against the unit T and positioned for passage beneath the set of units X upon the conveyor P where the iinal tinning operation is performed to coat the metallized margin d.

Each of the conveyor units are substantially identical in structure with one another; thus the aligning conveyors B, F, J and N are identical, as are the intermediate conveyors C, E, G, I, K, M, and O, and the tinning conveyors D, H, L and P. For this reason it will only be necessary to describe one conveyor of each type in detail, and this ca n best be done by referring to Figs. 6 and 7 of the drawings, wherein is illustrated a side elevation and plan view respectively of the rear end of the aligning conveyor F, intermediate conveyor G, tinning conveyor H, intermediate conveyor l, and the forward end of aligning conveyor J. v

Associated with the tinning conveyor H is the set of reducing, burnishing, uxing, and solder applying units V, and since all four of the sets of conditioning and tinning units U, V, W and X are substantially identical in structure and operation, a detailed description of the set V will be typical of all.

As explained above, before reaching the tinning line A, the glass sheet 20 to be tinned has been subjected to a suitable metallizing treatment to form a coating of metal 16 on the four margins a, b, c and d, thereof (Fig. 4). And, during passage over the first tinning conveyor D, the metal coating on the lower short margin a, as viewed n Fig. 4, is suitably tinned by the set of conditioning and tinning units U, so that when the glass sheet 20 reaches the aligning conveyor F (Figs. 6 and 7) it is provided with metal coatings on its four margins, and the metal coating on the margin a has been tinned.

It is then necessary to realign the glass sheet 20 as it moves over the conveyor F to properly position it for tinning the short metallized margin b. To accomplish this the conveyor F is so constructed that the sheet 20 is received on a plurality of rollers 21, arranged in rows and in endless belt formation (Figs. 8 and 9).A Thus, each row of rollers 21 is carried by angle bars 22, the stub axle 23 of each roller being secured in the upwardly extended leg 24 of the bar by a nut 25. The bars 22 are connected at their ends to a pair of roller chain belts 26 which are trained about sprockets 27 and 28 (Figs. 6 and 10); the shafts 29 and 30, respectively, for the sprockets 27 and 28 being journaled in the bearings 31 attached to the end of the frame 32 of the aligning conveyor F. As shown in Fig. 9, a clamping block 33 engages the surfaces of a pair of the links 34, comprising the roller chain belts 26, and a bolt and nut connection 35 serves to tightly secure the parts of the block with respect to the links. The said chain belts 26 are each supplied with supporting rollers 36 which are carried in tracks 37 located in the upper ends of the frame on framing angle members 38. The angle members 38 are attached to channel members 39 that extend crosswise between the legs 40 or end columns 41. The returning portions of the roller chain belts 26 are supported on a ledge 42 afforded by a welded construction 43 depending from the channel members 39. The shaft 30, which may be dened as the driving shaft of the conveyor F is suitably interconnected with the tinning conveyor H, as shown in Fig. 6, so that the pair of units can be driven from a common source as will be further described hereinafter.

During its movement across the conveyor F, the sheet 20 is shifted transversely, as shown in Fig. 8, against an articulated surface, or flexible wall, indicated at 44, that is moved at a rate of speed equal to that at which the bars 22 are moved by the roller chain belts 26. The surface is alforded by a series of resiliently faced plates 45 carried by a chain belt 46 (Fig. 11). The plates 45 have rubber pads 47 vulcanized, or otherwise attached, to one surface while the opposite surface is secured to the bent portions 48 of the attachment links 49 of the chain belt 46 by bolt and nut connections 50. 'The chain belt 46 is trained about a pair of sprockets 51 (Fig. 10) that are pivotally mounted in the ends of a case 52 (Fig. 13). A frame 53 for the case comprises upper and lower plates 54 and 55 spaced from each other by a bar 56 and to which the housing 57 of the case is secured to enclose the outer and top side portionsof the frame 53, as shown in Fig. 8; the inner side being open for movement of the glass against the rubber pads 47. The chain case 52 is mounted, with reference to the frame 32 of the conveyor F, on columns 58 to which the lower plates 55 are bolted. Preferably the pair of sprockets 51 are supported on shafts 59 and 60 that are journaled in bearing brackets 61 secured, as sen in Fig. 13, in the ends of the frame 53.

The plates 45, to which the pads 47 are attached, are restrained from deflection by a plurality of strips 62 that are bolted to the sides of the plates 54 and 55. Thestrips A 62 engage the top and bottom edges of the plates 45, as

' and are trained about seen in Figs. 8 and 12, and serve to maintain the series of plates in a straight line while also supporting them and the roller chain between the sprockets 51. The chain belt 46 is driven by one of the sprockets 51, as illustrated in Fig. 13, wherein the shaft 60 is provided with an extension 63 that is connected, through the sleeve 64, to the shaft 65 of a gear reducer unit 66. A gear 6 7 mounted on the opposed shaft 68 of the unit is connected to a sprocket 69 by a chain belt 70. The geary 69 is keyed to the shaft 30 so that rotation of the shaft 30 to move the roller chain belts 26 will be transmitted through the chain belt 70 and reducer unit 66, to also drive the sprockets 51 and chain belt 46.

The reducer unit 66 is adjustably mounted on a bracket 71 attached to the frame 32 and may be shifted as desired by loosening of the bolts 72. Any slack in the chain belt 70 may be compensated for by an idler gear 73 superimposed between the gears 67 and 69 and rotatably mounted on a stub axle 74 that is mounted in a bracket 75 on a part of the frame 32. The entire chain drive may be suitably enclosed by a cover or case 76 to prevent interference of operation and to maintain the parts in an orderly fashion.

After the glass sheet 20 has been properly aligned by the llexible wall 44 on the conveyor F, it will overhang the conveyor a short distance, as best shown in Fig. 8; in actual practice, a distance of about two inches. From the conveyor F, the aligned sheet is carried over the intermediate conveyor G and onto the tinning conveyor H where it is received and moved forward on a slat type conveyor belt 77 (Figs. 14 and 15) forming a part thereof. The belt 77 is made up of a plurality of channel members 78, each of which is provided with a resilient, cushioning surface afforded by a layer of rubber 79 vulcanized to the surface of the channel members. The ends of the .channel members are carried by a pair of roller chain belts 80 that move along the tracks 81 pairs of sprockets v82 and 83 (Fig. 43).

The pairs of sprocket gears are keyed to shafts 84 and located on the angular side members :88 of the frame which are supported, between the end columns 89, on framing channels 90. The framing channels are secured to the upper ends of the end columns 89 and intermediate legs 91. The returning sections of the roller chains are supported on a ledge 92-provided by a weldment 93 secured to the lower portions of the framing channels 90.

The shaft of the conveyor Hzis driven from a common source of power, or motor 94 through suitably mounted shafting which will be described later.

As shown in Fig. l5, the glass supporting channel members 78 of the conveyor belt 77 have clamping block portions 95 engaging ythe links of the roller chains, and which -are secured thereto by abolt and nut connection 96. By their manner `of common mount and interrelation, through'the roller chain vbelts 80, the channel members, when 'forming the surface lof the conveyor belt 77, provide a substantially smooth support for the glass sheet.

During movement of the sheet 20 past the various 'units of the set of reducing, burnishing and tinning units V, the sheet is held from rising, or shifting out of alignment, by hold-down devices 97, each of which is provided with rollers 98 which ride on the surface of the glass and, by reason of their method of support, exert a freely movable .downward weight. The rollers are positioned between side rails 99 that are interconnected by spacer blocks 100 (Figs. '24 and 25). The side rails have slots 101, formed to extend in a diagonal plane, for receiving the attened ends of the axles 102 of the rollers. These slots 101 are inclined upwardly in the direction of movement of the sheet '20 and so permit the rollers to move freely down into engagement therewith as it moves along the conveyor. At the same time, the hold-down rollers 98 can rise with and so accommodate varying thicknesses of sheets.

The rollers 98 are suitably located on and between bearing members 103 to reduce any frictionalresistance to their rotation and have cushioned peripheries, provided by the rubber tires 104, so that therewill be no injury to the surface of the glass during their engagement or roliing contact.

The side rails 99 of the hold-down devices 97 are suspended, above the glass sheet, from a frame 105 by threaded rods 106 that may be raised or lowered for positioning of the rollers 98 by movement of thelock nuts 107. The frame 105 comprises a pedestal 108 and arm 109 from which a flange 110 is extended for 'receiving the threaded rods 106. The base 11'1 of each pedestal 108 is bolted to a surface plate 112 that provides the top of an auxiliary frame 113. The frame 113 has leg supports 114 which are attached to the main frame 86 of the con-V veyor unit H by bolts extending through spacer blocks 115 and the weldments 93 of the main frame.

As the glass sheet 20 is thus moved along the line by the conveyor belt 77 and sustained from a tendency to rise or shift out of position by the accumulative weight of the rollers 98 on its'surface, the margin b that is to be solder coated, passes beneath the set of reducing, burnishing and tinning units V which are mounted above the tinning conveyor H upon the surface plate 112 of the auxiliary frame 113. As the `glass sheet is moved forwardly upon the conveyor H, the portion of the metal coating 16 designated b will be first conditioned and then tinned, as a part of the complete tinning operation, by the various units in the set V.

The first step of the complete tinning operation is to insure that the metal coating 16, which in commercial production is preferably a coating of copper, be perfectly clean and free from contamination. In some cases it may be desirable to wash yor otherwise clean the coating but where it is fed directly from the metallizing spray apparatus to the tinning units, it is only necessary to remove the oxides Ithat are formed by the exposure of the newly sprayed coating to the air.

This may be conveniently accomplished by the use rof a reducing ame or llames. In the past hydrogen flames have been employed for this purpose, but'we have found that the oxides can be satisfactorily reduced by a plurality of properly controlled natural gas flames. To this end the coated margin of the glass is rst passed beneath the reducing `or burner unit 116 of the set of tinning units V (Fig. 18). This unit comprises a pair of burner heads 117 arranged in tandem. These heads 117 are of the internal combustion type having elongated, ceramic lined combustion chambers into which a controlled mixture of natural gas and air is introduced and burned to produce a llame of reducing characteristics. The burner orifice of each head is similar in shape to the combustion chamber 'but is of restricted area as shown in Figs. 17 and 18.

The heads are attached to Vsupport pipes 118 by pipe elbows 119. The pipes are mounted in a plate 120 having bosses 121 through which the pipes extend and in which they are secured by set screws 122. The burner heads may thus be positioned with reference to the neighboring units and the glass edge before adjustment of the set screws. The plate 120 is carried by a standard 123, means being provided by the slots 124 and bolts 125 for obtaining the desired height of the burnerheads. In actual practice we have found that best results are obtained with the burners from 1/2 to 3A of an inch above the glass. The standard 123 is attached to the surface plate 112 by bolts extended through the base plate 126.

Each of the pipes 118 has a manual control valve 127 for modifying the intensity or the effectiveness of the ame, as shown at 128, in Figs. 17 and 18. The pipes are connected to a common supply pipe 129 that extends to a source of supply and to protect the machine against explosion or conagration, suitable fire trapping devices 130, such as are shown in Fig. 43, may be located in the supply pipe 129 so that upon the occurrence of an incorrect mixture, or other contingencies, with a resultant transmission of the flame into the pipe, the device 130 willautomatically close to shut ot the gas supply in a manner well known in the art. As already indicated, it is necessary to operate the burner heads 117 at a temperature that will reduce the oxides, but at the same time it is essential that the glass not be allowed to become too hot because excessive heat will result in reoxidation of the metallic coating.

When the oxides have been reduced in the manner just described it will be found `that weaker solutions of flux may be used in the subsequent tinning operations without any time being lost for the reaction of the flux to vtake place.

Upon leaving the reducing flames, the metal coated glass margin b passes beneath a burnishing unit indicated generally at 131 for the purpose of smoothing and leveling the copper coating prior to the actualr tinning, and to remove any lremaining oxides. This unit is best indicated in Figs. 6, 7, 16 and 2l to 23 and comprises three wire brush Wheels 132 which, in rotating on the metallic coating 16, abrade and level the peaks from the surface of the coating. In the spray gun method ordinarily employed forv deposition of the copper or copper alloy, it has been found virtually impossible to obtain a minutely smooth surface since the .interlaying particles of the alloy from a characteristically ridged effect if inspected microscopically. The peaked, or ridged, effect thus produced prevents an even layer of solder by reason of the fact that during the solder coating, the ilow inducing element engages and rides on the obstructing peaks without contacting the lower areas of the metallic coating surface and thereby leaves an irregular solder coat surface. The brushes 132, therefore, smooth out the higher points of the copper deposition and induce the preparation of an even surface over the entire metallized coating.

We prefer that the brushes 132 be wire brushes. Wires having a diameter of .003" have been successfully used for this purpose, be we ,believe that wire diameters of .004" "may be even better.

ansehe@ Y Besides the brushes 132, the unit 131 includes a motor 133 and a supporting frame 134 for the unit. Each of the brushes 132 is clamped to a shaft 135 by washer 136 and a nut 137 threaded onto the end of the shaft. Each shaft is journaled in a bearing sleeve 138. The sleeves are bolted to angle pl-ates 139, which form the side rails of a movable carriage or support 140 and are interconnected at their ends by bars 141. The surfaces of the opposed leg portions 142 of the angle plate 139 slidably engage the sides of stationary standards 143 of the frame 134. The rectangular movable sup4 port 14!) thus provided for the brushes 132 is adjustably sustained at any desired height by means of bolts 144 located in the bars 141 and having lock nuts 145 threaded thereon. The ends of the bolts 144 rest on blocks 146 which in turn are supported on the surfaces of cam members 147 (Fig. 21). The blocks 146 are interconnected 4by straps 148, attached by welding to the blocks and extending `along the sides of the standards 143 below the angle plates 139. Upon rotation of a shaft 149, on which the cams 147 are mounted, the blocks 146 will urge the rectangular support 140 upward or downward according to the differential of distance between any of the surfaces 150 of the cams 147 and the bearing surface 151 thereof which support the cams with reference to the base 152 of the stationary fr-ame 134.

The brushes 132 rnay Iaccordingly be adjusted for varying thicknesses of glass to assure an effective burnishing of the metallic coating with a uniformity of result. Preferably, the web of the standards 143, which may be fabricated from channel iron, has slotted openings 153 for movement of the shaft 149 upon its rotation by a lever 154 to elect a change in height of the brushes 132 with reference to the glass surface. The bolts 144 may also be individuallymanipulated to level the relation of the support 140 to the blocks 146, or the relation of the two outer brushes 132 with reference to each other and to the surface of the glass.

When the desired position for the brushes 132 has been obtained, the rectangular support 140 is secured from any .movement by a pair of bolts 155 that are threaded into cap plates 156 secured at the tops of the standards 143. As shown in Fig. 20, the bolts are threaded into engagement with clamping bars 157 that are located in notches 158 lprovided in the leg portions 142 of the angle plates 139. Having tightened the bolts 155 against the bars 157, the lock nuts 159 m-ay be turned to lsecure the screws from any loosening rotation. The rectangular support 140 for the brush shafts 135 will thus be held from movement, and rattling or shaking of the related parts will be substantially impossible.

The lever 154 is keyed to one end of the shaft 149 and its position, according to the surfaces 150 of the cams 147, may be determined by a locking plate 160 which is bolted to an end of the base 152. The locking plate has a number of notches 161 for receiving a latching bolt 162 carried by the lever 154. As shown in Fig. 23, the notches 161 are located in the periphery of the plate 160 in -angular registry with the positioning of the surfaces 150 of the cams 147 with respect to the blocks 146 and upon selection of the correct surfaces to procure the desired brush height, a clamp unit 163 on the bolt 16 2 may be turned to lock the lever to the plate 160.

In order that the motor 133 may be suitably mounted and that the drive between the motor and shafts 135 will not require adjustment after change of position of the rectangular support 140, a mounting plate 164 for the motor is carried by the said support. As shown in the drawings, the mounting plate 164 is pivotally connected at one end by a rod 165 to a pair of suitably bent frame members 166. The frame members are secured to the angle plates 139 (Fig. 19.). The opposite end of the 755 plate 164 is adjustably supported by a bolt 167 having nuts 168 threaded against surfacesv of the plate. The bolt 167 is attached by welding to a rod 169, the ends of which are located in collars 170 secured to the frame members 166. I

The shaft of the motor 133 has a pulley 171 mounted thereon which receives a double V belt 172 to drive pulleys 173 mounted on the shafts 135. The belt is trained about the pulleys 173 to rotate the outer shafts in one common direction while the intermediate shaft 135 is yrotated in the opposite direction. The brushes 132 accordingly perform their abrading, or burnishing, functions on the metallized coating 16 in such a manner as to assure that smoothing of the ridges, or peaked areas, of the coating will be effected regardless of the angle at which they project from the general surface. To compensate for the tension condition of pulley belt 172, the nuts 168 may be shifted on the bolt 167 to raise or lower the motor mounting plate 164 with reference to the common axial plane of the shafts 135. If desired, to prevent undue throwing -of the abraded particles and, at the same time, afford a suitable guard for the brushes 132, a case as indicated at 174 may be secured to the rectangular support 140.

From the abrading unit 131, the properly conditioned metallized margin b ofthe glass sheet moves beneath a uxing unit indicated generally at 175,A and best shown in Figs. 26 to 29. This unit includes a flux applying wheel 176 which receives quantities of ux, during contact with the glass, from a reservoir 177 through an electrically controlled valve 178. The ilux is employed as a matter of precaution, to insure the utmost of cleanliness and to obtain a permanent and satisfactory union between the metallic coating 16 and the solder coat to be applied thereto. Preferably, the flux is applied in liquid form as the metallized glass sheet passes in rolling contact beneath the wheel 176.

Various combinations of stock uxes can be used for the purpose, but we have had best results with a dilution of a mixture of 37.5 pounds of abietic acid (commercial grade), 46.5 pounds of triethanolamine and 46.55 pounds of diethylene glycol. One part of this mixture is preferably diluted with eight parts of a diluent, and we -prefer isopropyl alcohol for this purpose.

A ux of this dilution will flow easily and we have determined that a suicient amount of the flux will be made available when it is fed at the rate of two drops per second when the conveyor is moving at approximately twenty Ifeet per minute. This amount will adequately cover the metal coating and at the same time will not result in an objectionable liooding of the exposed glass surface.

At this rate of feed, the felt, or similar composition, band 179, forming the outer surface of the wheel 176, is constantly saturated and the periphery 180 of the wheel, to which the band 179 is secured, is perforated, as at 181 (Fig. 28), so that the saturation will be uniform, while the flange 182 has sufcient width to allow retention of 'a quantity of the ilux within the wheel. To prevent puddling or gatheringof the liquid in one area, particularly the lower portions of the -felt band, the wheel 176 is rotated continuously during the interval betwen its riding contact with the glass sheets. The wheel is mounted on a shaft 183 carried by a yoke type lever arm 184. Exterior to the arm. 184, a second wheel 185 is mounted on the shaft 183. The wheel 185 is smaller in diameter than the Wheel 176 in order that it will not engage the edges or surface of the glass. However, when the wheel 176 leaves the following edge of the glass sheet, it will permit riding engagement of the wheel 185 on the surfaces of the channel members 78 of the conveyor belt 77. The smaller wheel will thus revolve the shaft 183 and wheel 176 to prevent the flux frontl

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